This invention relates to the x-ray imaging of automobiles to detect explosives, hidden persons, contraband, and other security threats.
Criminals and terrorists frequently conceal security threats in automobiles, such as explosives being transported into underground parking facilities for the purpose of destroying skyscrapers; illicit drugs being smuggled across borders; and illegal immigrants being brought into the country. Searching the automobile by visual inspection is time consuming and often ineffective. For instance, persons and contraband hidden in the dashboard or within the seats cannot be visually detected. X-ray inspection systems are now in use that can detect these security threats to some extent. These prior art systems use x-rays that are either transmitted through the automobile, or back scattered from the automobile, to form an image. The x-ray image is inspected by the security personnel to detect the presence of hidden security threats. However, prior art systems cannot readily distinguish the organic matter that comprises security threats from the steel forming the automobile. Further, this inability prevents the prior art systems from employing automated threat detection software programs. Still further, prior art systems are inefficient in producing contraband-revealing images at the ultra-low radiation doses that are acceptable for such security examination.